It's my intention to post some pictures of this sub-chassis fairly soon, but whilst I'm listening to the results I thought I'd get the thread started.
My LP 12 is a very early model and I've given up on using Ebay as a source of affordable secondhand Linn spares, (prices have just gone crazy IMO. Only component I managed to get hold of was a later 80's Afromosia corner braced plinth), so I've decided to make my own improved components?
List as follows:
1. Constrained layer sub-chassis using 10mm MDF core sandwiched between two 1mm aluminium sheets all epoxy glued together; result = a very stiff and slightly heavier subchassis which seems acoustically dead as the proverbial to resonances. Thought I'd try it out at approx 90 or so grams heavier than the pressed steel early sub.
2. A new aluminium main bearing housing with a 50 mm diameter flange into which the standard non Cirkus main bearing fits.. This pair of components are then screwed to the top of the subchasis providing a very rigid assembly.
3. A new brushed stainless steel top plate into which I've cut the motor hole as per the Pink Linnk. I've used dampening pads on the underside of the top plate to reduce resonances, and the motor has been isolated from the top plate uasing a cork gasket. I've also epoxied hardwood block onto each corner of the top plate and used thse to pass screws through from below to tension the top plate down onto the plinth.
4. Given the stronger & more acoustically inert properies of the sub-chassis I've decided to use M4 csk Allen socket screws inserted from above and done up good and tight to attach the armboard effecively making the amboard and sub one component. I guess similar to the Cetech set up ?
5. I've dispensed with the four feet and opted for 3 - two at the front and one at the rear in order to reduce any chance of rocking and allow for ease of leveling the plinth on its base.
This has all taken a very long time and a bucket load of hard work but I think the result has been worth it..
Early listening impressions? Well gone has that well known Linn "hole in the middle" effect, sound stage is wider than my Rega P25. Bass good-n tight, transients very sharp and treble nice and sweet. All this with a cooking SME 3009 series 3 and Shure V15 2 But don't think I'll be rushing back to the P25 in a hurry! Total cost of all materials approx £ 35. Hoping to post pics on the W/E.
alf.
My LP 12 is a very early model and I've given up on using Ebay as a source of affordable secondhand Linn spares, (prices have just gone crazy IMO. Only component I managed to get hold of was a later 80's Afromosia corner braced plinth), so I've decided to make my own improved components?
List as follows:
1. Constrained layer sub-chassis using 10mm MDF core sandwiched between two 1mm aluminium sheets all epoxy glued together; result = a very stiff and slightly heavier subchassis which seems acoustically dead as the proverbial to resonances. Thought I'd try it out at approx 90 or so grams heavier than the pressed steel early sub.
2. A new aluminium main bearing housing with a 50 mm diameter flange into which the standard non Cirkus main bearing fits.. This pair of components are then screwed to the top of the subchasis providing a very rigid assembly.
3. A new brushed stainless steel top plate into which I've cut the motor hole as per the Pink Linnk. I've used dampening pads on the underside of the top plate to reduce resonances, and the motor has been isolated from the top plate uasing a cork gasket. I've also epoxied hardwood block onto each corner of the top plate and used thse to pass screws through from below to tension the top plate down onto the plinth.
4. Given the stronger & more acoustically inert properies of the sub-chassis I've decided to use M4 csk Allen socket screws inserted from above and done up good and tight to attach the armboard effecively making the amboard and sub one component. I guess similar to the Cetech set up ?
5. I've dispensed with the four feet and opted for 3 - two at the front and one at the rear in order to reduce any chance of rocking and allow for ease of leveling the plinth on its base.
This has all taken a very long time and a bucket load of hard work but I think the result has been worth it..
Early listening impressions? Well gone has that well known Linn "hole in the middle" effect, sound stage is wider than my Rega P25. Bass good-n tight, transients very sharp and treble nice and sweet. All this with a cooking SME 3009 series 3 and Shure V15 2 But don't think I'll be rushing back to the P25 in a hurry! Total cost of all materials approx £ 35. Hoping to post pics on the W/E.
alf.
